The present invention is directed generally to a method and apparatus for measuring a key, in particular a method for measuring a key in order to make a subsequent duplicate of the key.
Hundreds of millions of keys are generated in the United States each year by making a duplicate from an original key or from a parent duplicate key. The duplication process commonly takes place in a hardware store, or the like, that is equipped with a key duplication machine.
Duplicating a key is difficult task, typically requiring high skill in operating the duplicating machine. A high degree of skill is particularly required when duplicating a double sided key in order to achieve correct registration of the second side after cutting the first side. Due to the high probability of making an error when duplicating a key, a significant number of the duplicate keys made each year are discarded as being unusable.
Since there is a wide variation in the types of keys manufactured, the locksmith or hardware store where the duplicate is made has to carry a large number of different key blanks, often numbering in the thousands, in inventory from which an appropriate blank is selected for forming the duplicate key. When faced with duplicating a key of unknown origin, the person performing the duplication is presented with the difficult task of selecting the correct key blank with which to manufacture the duplicate. This may lead to the selection of the wrong key blank, thus resulting in an unusable duplicate key.
The security hierarchy adopted by many key manufacturers includes thicker keys with relatively complex keyways for use in single locks, and master keys that are thinner and have relatively simple keyways. Often, master key blanks are employed for forming duplicate keys in an attempt to reduce the number of key blanks required in inventory, irrespective of whether the key being duplicated is a master key or is cut for a single lock. Consequently, the security hierarchy is compromised when a large number of keys cut from master key blanks enter into use.
One manufacturer has adopted a system that uses a small number of key blanks in which it is claimed most keys can be duplicated, thus reducing the level of skill required of the person performing the duplication. However, this system still requires a significant inventory of different key blanks and, additionally, is subject to the problem of low-skilled operators making a large number of rejectable duplicate keys.
Therefore, there remains a need for a key duplicating system which further reduces the number of types of key blanks required to be carried in inventory. Additionally, there is a need to remove the factor of operator skill level from the duplication process so that fewer rejectable duplicate keys are manufactured.
Generally, the present invention relates to an apparatus and method for measuring the original key from which a duplicate key is to be made. In particular, the method permits measurement of the keyway and the keycode so that machining instructions may be developed to form the duplicate key using the measurements of the keyway and keycode of the original key.
In one embodiment, the invention is directed to a method of measuring an original key having a keyway on a major surface of a key shaft. The method comprises illuminating the major surface of the key shaft with a line of light focused approximately on the major surface of the original key, the light propagating in a direction substantially perpendicular to an axis of the original key parallel to the shaft. The method also comprises detecting light deflected from the light beam by the surface of the original key at an angle non-perpendicular to the major surface.
In another embodiment, the invention is directed to a system for measuring an original key having a keyway on a major surface of a key shaft. The system includes means for illuminating the major surface of the key shaft with a line of light focused approximately on the major surface of the original key, the light propagating in a direction substantially perpendicular to an axis of the original key parallel to the shaft; and means for detecting light deflected from the light beam by the surface of the original key at an angle non-perpendicular to the major surface.
In another embodiment, the invention is directed to a system for measuring an original key having at least one groove in a first major surface of a key shaft forming a keyway. The system comprises a key holder to hold the original key in a pre-selected position with the key shaft approximately parallel to a first axis and a light source producing a beam of light directed substantially perpendicular to the first axis towards the first major surface. The system also includes a light detector positioned to receive light deflected in a direction substantially non-perpendicular to the first axis when the original key is held in the key holder at the pre-selected position.
The above summary of the present invention is not intended to describe each illustrated embodiment or every implementation of the present invention. The figures and the detailed description which follow more particularly exemplify these embodiments.